This invention relates to a lading sampling device. In particular, it relates to a lading sampling device for taking a sample of the lading at a given level in the tank only. Thus the composition of the lading at various levels in the tank can be analyzed and compared to samples taken from other levels.
One common lading sampling technique is to rely on pressure in the tank which exceeds the atmospheric pressure to force a sample out. For example, as described in U.S. Pat. No. 1,669,776, a hollow sampling tube open at the inlet end and closed at the outlet end with a valve or removable plug is lowered to the level in the tank where a sample is desired. The outlet end is opened to the atmosphere and the pressure in the tank above atmospheric forces the sample from the given level out of the tank.
U.S. Pat. No. 1,739,731 discloses a pair of concentric sampling tubes including an outer guide tube containing perforations throughout its length. A sampling tube without perforations is lowered longitudinally within the guide tube to obtain a vertical core sample of all levels in the tank. On page 1, col. 1, this patent refers to prior use of telescoped, relatively rotatable tubes provided with perforations in each tube at various levels adapted to register for admission of a sample and to be moved out of registry to trap the sample. There is no indication that the openings located at any one level were circumferentially spaced from the openings at other levels in either of the tubes. Thus, apparently this prior technique was directed to taking a sample from all levels in the tank rather than to taking a sample from a selected level only.